title: From sulfur-amine solutions to metal sulfide nanocrystals: peering into the oleylamine-sulfur black box.
abstract: In this Article, we present our findings on the formation of metal sulfide nanocrystals from sulfur-alkylamine solutions. By pulsed field gradient diffusion NMR along with the standard toolbox of 1D and 2D NMR, we determined that sulfur-amine solutions used as a sulfur precursor exist as alkylammonium polysulfides at low temperatures. Upon heating to temperatures used in nanocrystal synthesis, the polysulfide ions react with excess amine to generate H(2)S, which combines with the metal precursor to form metal sulfide. Four different reaction pathways were found, each of which produced H(2)S and the byproducts identified in this Article. Thioamides were identified as an intermediate and were shown to exhibit much more rapid kinetics than sulfur-alkylamine solutions at low temperatures in the synthesis of metal sulfide nanocrystals.
authors.affiliation: Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Thomson
authors.forename: Kaz
authors.initials: K
authors.lastname: Nagashima
authors.forename: Peter M
authors.initials: PM
authors.lastname: Macdonald
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Ozin
mesh_terms: D000588:Amines / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry*; D012996:Solutions; D013440:Sulfides / Q000737:chemistry*; D013447:Sulfites / Q000138:chemical synthesis / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013696:Temperature
chemical_list: D000588:Amines; D008670:Metals; D012996:Solutions; D013440:Sulfides; D013447:Sulfites; D013455:Sulfur; C042345:hydrogen sulfite